TOP will display a full screen of information about the processes running on the system, as well as some overall information about the system.This includes load average, number of processes, the CPU status, freememory information, and details about processes including PID, user, priority, CPU and memory usage information, running time, and program name.

$>top        -it will display the complete active process, cpu and memory information.
SHIFT+M -Memory使用率由高到低排序
SHIFT+P  -CPU使用率由高到低排序
SHIFT+W -For saving the top outputin a file(/root/. toprc.)
SHIFT+F -設定顯示列，以及預設按哪個排序

s：更改top重新整理時間，預設3s

i：隱藏idle狀態的程序，只顯示當前活躍的程序

k：殺程序，後面跟程序ID